The effect of time and temperature on flexural creep and fatigue strength of a silica particle filled epoxy resin

摘要

Composite materials that use an epoxy resin as amatrix resins have superior mechanical properties over standardstructural materials, but these materials exhibit time andtemperature behavior when used for long periods and under hightemperatures. This time and temperature behavior has not beenfully explained. The purpose of this paper is to further describe thistime and temperature behavior, increasing the reliability of thisclass of composite materials. The time and temperaturedependence of flexural strength was examined by creep and fatiguetesting. Flexural creep tests were carried out at varioustemperatures below the glass transition temperature. Flexuralfatigue tests were carried out at various stress ratios, temperaturesbelow the glass transition temperature and 2 frequencies. Thetime-temperature superposition principle held for the flexuralcreep strength of this material. A method to predict flexural creepstrength based on the static strength master curve and thecumulative damage law is proposed. When the fatigue frequencywas decreased while temperature and stress ratio are held constantthe flexural fatigue strength decreases. The time-temperaturesuperposition principle was also found to hold for the flexuralfatigue strength with respect to frequency.